1. Field of the Invention
The present invention relates to identification cards and, more specifically, to the use of micro-printing on such cards to inhibit the alteration or forgery of such cards.
2. Description of the Related Art
There are a large number of documents which are commonly used to identify individual people or objects, or which represent or convey financial value. Driver's licenses and employee badges are two examples of highly prevalent identification documents. Identification documents may also be employed with objects. Such documents may be used to establish that a particular object has been inspected, passed through customs or possesses some other attribute which affects its value. For example, an identification document may be used to establish the provenance of an artwork or the pedigree of an animal. Documents may also be employed as financial instruments such as money orders and stock certificates.
The value of these identification documents provides an incentive for the unlawful alteration or counterfeiting of such documents. A large variety of means, both simple and sophisticated have been developed to hinder the alteration and counterfeiting of such documents.
A relatively simple and cost efficient type of identification card for an individual typically contains textual matter pertaining to the specific individual identified in the card, such as the person's name, address, date of birth and some type of identifying number such as a driver's license, social security or other unique serial number. The card may also contain information on the person's physical characteristics such as hair color, eye color, height and weight and display the person's signature and photograph.
Such cards are not fool-proof, however, and it is not uncommon for individuals to attempt to alter such documents by changing some of the printed text found on the card or by substituting a different photograph. For example, alterations to the date of birth on such cards may be made by minors who wish to illegally purchase alcohol or such individual may attempt to substitute their own photograph in a card which identifies an older individual.
To prevent such tampering and the production of counterfeit cards, identification cards may employ various well-known deterrent methods. For example, the card may contain elements which are difficult to replicate such as holograms. The cards may also be constructed of materials which are destroyed upon an attempt to tamper with the card. The cards may also employ means to record data which cannot be directly read by a human viewer such as magnetically recorded or bar coded data. This recorded data may also be encrypted to provide further security. Micro-printing, which cannot be easily read without magnification and which is often found on paper currency, may also be used. The difficulty of faithfully reproducing the micro-printed text inhibits the production of counterfeit documents. A brief review of several of these methods can be found in U.S. Pat. No. 5,284,364.
These measures provide different levels of deterrence. Generally, the more sophisticated measures provide a greater measure of security but at a higher level of cost.